Omeprazole 20 mg side effects

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Omeprazole in 20 mg dosages is a medication used to treat conditions caused by stomach acid, such as heartburn, gastro-oseophageal reflux disease (GERD) and gastrointestinal ulcers. The drug is available as Prilosec and in generic form, both by prescription and over the counter. Side effects are uncommon.


Omeprazole is a proton pump inhibitor (PPI), a type of drug which blocks the production of stomach acid. Reducing stomach acid prevents acid reflux, and allows ulcers and esophageal damage to heal.

More Common Effects

Although most people do not experience side effects when taking omeprazole, many are possible. Side effects can include back pain, muscle pain, dizziness, headaches, upper respiratory tract infections, constipation, diarrhoea, nausea and stomach pain.


Rare severe omeprazole side effects include allergic reactions and pancreatitis. People with liver disease should not take over 20 mg daily because higher doses can elevate liver enzymes, indicating impaired function.

Time Frame

Proton pump inhibitors, including omeprazole, are intended for treatment lasting four to eight weeks, but many people take the drug for years. Long-term use is linked to an increased frequency of hip fracture in people over 50, and of colitis caused by the Clostridium bacteria.

Drug Interactions

Omeprazole interacts with many drugs. Examples include anticoagulants, diazepam, digoxin, phenytoin, and drugs used to treat infection caused by the human immunodeficiency virus (HIV).

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